Prostheses often are implanted during surgical or other medical procedures to aid in repair of defects, reinforcement of a target site, delivery of therapeutic, or to serve other medical purposes. For example, hernia patches or other similar prostheses are commonly implanted using open or laparoscopic techniques. Such techniques can be useful in treating central hernias as well as small hernias, e.g., umbilical or epigastral defects.
For instance, open procedures are performed by making a single incision through which a hernia patch is inserted for implantation to the target site. Typically, the hernia patch is rolled up or otherwise compacted prior to insertion so as to enable greater ease of passage through the single incision and to the site of the defect. Once the hernia patch is appropriately positioned within the body (e.g., in the abdominal cavity, in the pre-peritoneal space, etc.), it can be unfolded, unrolled, un-collapsed, or otherwise caused to assume a deployed, generally planar configuration.
However, deploying the hernia patch in this manner is a cumbersome task that requires skillful manual manipulation. Even then, it is often difficult for an adept surgeon given that such a task is performed under several layers of tissue. Furthermore, manipulation of the hernia patch can prove to be an even greater challenge in the case of laparoscopic procedures, since trocars used to implant the hernia patch provide limited range of motion, thereby requiring the surgeon to utilize small instruments and graspers.
Several existing mesh patches provide a base layer of mesh with second or third layers that form pockets, aprons, or other enclosures intended to aid in the manipulation and fixation of the mesh. Furthermore, among these, some mesh patches include a rigidified perimeter and/or a rigid ring or frame attached near a perimeter of the patch to cause the patch to assume a deployed, generally planar configuration once inserted into a patient. In some instances, the ring or frame is constructed from biodegradable material that can be absorbed over time. These absorbable rings or frames tend to lack sufficient strength or can potentially interfere with the intended functionality of the patch, e.g., tissue in-growth or reinforcement. In other instances, the ring or frame is formed of non-absorbable material (e.g., polypropylene, PTFE, etc.) and thus remains a permanent structure within the body. These patches tend to exhibit greater strength, but consequently may interfere with the functionality of the patch. For example, permanent rings can form additional contours that can create points of tension at particularly undesirable positions on the surface of the patch. Still other attempts to facilitate deployment provide a monofilament or wire ring that is crimped or sintered in order to adjoin the ends, which create yet additional weak points that historically have been associated with higher risk of failure, health complications, and even death after implantation.